In order to study the issue of polarization state transmission in parallel phase-shifting coaxial digital holographic system, a modified model of parallel phase-shifting coaxial digital holographic system considering polarization is proposed, and a polarization imaging method is proposed based on this model.Firstly, the principle of parallel phase-shifting coaxial digital holography under ideal conditions is introduced.Then, the modified model of parallel phase-shifting coaxial digital holography considering polarization is introduced.Finally, based on this model, a polarization imaging method is proposed.The experimental results verify the reliability of the model.The appearance information can be obtained by using this method, and the imaging resolution can reach 14 μm.This method expands the functions of digital holographic system.Through this system, the polarization state of the object can be imaged.